I see its different from the previous gen that used a screw like the TM to secure the rail on the other end. I guess KWA figured out that it a bolt would be tougher than a screw and t would take full advantage of the metal receiver. Great fix Allizard!

There has been a couple reports of loose Top Rails on the SR series and the new 2nd Gen receivers on standard KM4A1 and KM4 RIS.

After some investigation we have a quick and easy fix for the loose Top rails issue. Apply this fix ONLY if your top rails is loose.

Preparation
A punch size 1/16
A Hammer
A Shim or Spacer, size may vary (for our example we use .2 mm)

Step 1
Separate top receiver from the gun

Step 2
Remove hop-up and inner barrel out of the gun

Step 3
Rest the top receiver on it's side, locate the roll pin in the front and drive the pin out with punch and hammer.

Step 4
Remove the pin and keep in a safe place.

Step 5
Pull the charging handle back slightly and push the top rail backward.

Step 6
Once the top rail slide back you can lift the rail up from the front and remove from receiver.

Step 7
Place a shim to act as a spacer in the top front of receiver. You might need to try different size depend on the gap.

You can add a drop of glue to secure the spacer/shim. Optional!

Step 8
Place top rail back on receiver.

Step 9
Make sure the rail is lined up, flip the receiver to the opposite side.

Step 10
Place roll pin back in receiver and line up with top rail.

Step 11
Drive Roll pin back in receiver and the rail should be secure.

Depend on the size of the shim or spacer. It might be a little big and stick out in the front. You can file it down or use a smaller size.

Let us know if you have any further questions.

FYI, I just did this mod to my SR5. I used a piece of flat brass stock 1/64th thick. I placed it slightly further back than Spiggy shows in this post and so that it would not protrude. It's actually seated on the "U" shaped piece just behind the receiver shell. I am happy to report it worked like a charm. The shim was cut square about 3/16" x 1/4" and super glued for placement. Easy fix.

i have about 50,ooo rounds throught my gun KM4-RIS G2. the rail became loose around 30k..then just this past weekend the pin feel out.. good thing i had zipties. this part is not avalible and i cant seem to find this oddball sized pin. i called the proshop and i havent recieved a call back. how hard is it to look up a dang part number. so my gun is going to have to sit the next few games out...come one KWA get some part out for the G2 KM4. i just want to buy them and apparently you guys dont have them..Love the gun but hate all the BS..

Why dont my local shops have any of your replacement parts..they say you guys are not making them avalible.. should i go get another CA(Crapy AEG)?

1. When did you call? What time?
2. Which part it fell out? You got a picture where the missing part suppose to be? Part #?
3. Isn't "Existing Products" and "Current Products" mean the same thing?

1.about 10:00am cali time monday morning 5/10
2.part #127
3.not really.. i was thinking they sent me a older model possibly..i purchesed in Feb of 2010

i also asked for part #'s 3, 205,127 and a part which isnt listed-->my selector switch came loose and when i tried to pop the plug(selector dummy plug) out of the oppisite side to access the screw it broke i can make it work but was going to get a new one since i was going to make an order. i still havent heard anything back. please update the parts listing for the SR and KM4 series it is a pain to have to do all this reserch just to order a part. i had to mix and match. and some parts dont even exist..i would like to play sunday and i have the feeling i will not be going. please resolve this asap so i can get M4 running.. thanks

I noticed this problem on my M16 BR I got in august this year. I will try this out. I can imagine the possibility of making a carry handle that replaces the rail, to make it look like an M16A2 since it was so easy to take the rail off. Would be a lot better than buying a whole G&P upper receiver for my ranger loadout.